own integer ATOM1=17

routine CODEATOM

   if ATOM1#0 then ->i77L231
      ATOM1=19
      return
   i77L231:

   !Atom1 = ¬Atom1;  Atom1 = ¬Atom1
   return

   Print String("Error!");  Newline;  stop
end

begin
   Print String("About to call Code Atom");  Newline
   Code Atom
   Print String("atom1=");  Write(Atom1, 0)
   Newline
endofprogram